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Letteratura scientifica selezionata sul tema "Titania (Chemical)"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 18 febbraio 2022

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Articoli di riviste sul tema "Titania (Chemical)"

Rodríguez-Páez, J. E., A. Mafla, G. Andrade e A. Durán. "Modificación química del precursor de titanio para obtener soles estables de silice â titania: Uso de acetilacetona". Boletín de la Sociedad Española de Cerámica y Vidrio 43, n. 1 (28 febbraio 2004): 53–55. http://dx.doi.org/10.3989/cyv.2004.v43.i1.1044.

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Shyue, Jing-Jong, Rebecca E. Cochran e Nitin P. Padture. "Transparent-conducting, gas-sensing nanostructures (nanotubes, nanowires, and thin films) of titanium oxide synthesized at near-ambient conditions". Journal of Materials Research 21, n. 11 (novembre 2006): 2894–903. http://dx.doi.org/10.1557/jmr.2006.0352.

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A template-based, electroless wet-chemical method for synthesis of nanotubes and nanowires of nanocrystalline anatase titanium oxide (titania) at 45 °C is reported. Single-nanowire electrical property measurements reveal low dc resistivities (7–21 × 10−4 Ω cm) in these titania nanowires. In the presence of 1000 parts per million of CO gas at 100 °C, the resistivity is found to increase reversibly, indicating low-temperature gas-sensing capability in these titania nanowires. Thin films of nanocrystalline anatase titania, deposited using a similar wet-chemical method, also have low room-temperature dc resistivities (6–8 × 10−3 Ω cm), and they are transparent to visible light. Nanostructure-properties relations, together with possible electrical conduction, optical absorption, and gas-sensing mechanisms, are discussed. The ability to fashion transparent-conducting and gas-sensing nanocrystalline anatase titania into nanotubes/nanowires and thin films at near-ambient conditions could open a wider field of applications for titania, including nanoelectronics, chemical sensing, solar cells, large-area windows and displays, invisible security circuits, and incorporation of biomolecules and temperature-sensitive moieties.

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Garrick, Sean C. "Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows". Journal of Nanotechnology 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/642014.

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Titanium dioxide (titania) is used in chemical sensors, pigments, and paints and holds promise as an antimicrobial agent. This is due to its photoinduced activity and, in nanostructured form, its high specific surface area. Particle size and surface area result from the interplay of fluid, chemical, and thermal dynamics as well as nucleation, condensation and coagulation. After nucleation, condensation, and coagulation are the dominant phenomena affecting the particle size distribution. Manufacture of nanostructured titania via gas-phase synthesis often occurs under turbulent flow conditions. This study examines the competition between coagulation and condensation in the growth of nanostructured titania. Direct numerical simulation is utilized in simulating the hydrolysis of titanium tetrachloride to produce titania in a turbulent, planar jet. The fluid, chemical, and particle fields are resolved as a function of space and time. As a result, knowledge of titania is available as a function of space, time, and phase (vapor or particle), facilitating the analysis of the particle dynamics by mechanism. Results show that in the proximal region of the jet nucleation and condensation are the dominant mechanisms. However once the jet potential core collapses and turbulent mixing begins, coagulation is the dominant mechanism. The data also shows that the coagulation growth-rate is as much as twice the condensation growth-rate.

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Lee, Siew Ling, Jamilah Mohd Ekhsan, Nur Azleena Kasiran e Azira Abdul Aziz. "Effect of Titania Loading on Properties and Catalytic Activity of Nanostructured Phosphate–Vanadia-Impregnated Silica–Titania Oxidative–Acidic Bifunctional Catalyst". International Journal of Chemical Reactor Engineering 13, n. 1 (1 marzo 2015): 21–28. http://dx.doi.org/10.1515/ijcre-2014-0095.

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Abstract Effect of titania loading on physical–chemical properties and bifunctional catalytic activity of phosphate–vanadia-impregnated silica–titania was investigated. Different concentrations of titanium were impregnated into fumed silica, followed by impregnation of vanadium and phosphoric acid simultaneously onto the prepared silica–titania. Results revealed that Ti amount did not have significant effect on crystallinity, surface area and particle size of the resulted materials. However, quantity of tetrahedrally coordinated Ti species increased with increasing Ti content in the sample. Pyridine adsorption study showed the presence of both Brønsted and Lewis acid sites in all the samples even in the titanium-free phosphate–vanadia-impregnated silica sample. The catalytic testing showed that phosphate–vanadia-impregnated silica–titania with the molar ratio of Si:Ti=33:1 was the best bifunctional catalyst in the transformation of 1-octene to 1,2-octanediol using aqueous hydrogen peroxide as oxidant.

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Kartaev, E. V., V. P. Lukashov, S. P. Vashenko, S. M. Aulchenko, O. B. Kovalev e D. V. Sergachev. "An Experimental Study of the Synthesis of Ultrafine Titania Powder in Plasmachemical Flow-Type Reactor". International Journal of Chemical Reactor Engineering 12, n. 1 (1 gennaio 2014): 377–96. http://dx.doi.org/10.1515/ijcre-2014-0001.

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Abstract Methods for controlling the synthesis of the submicron (including nanosized) powder of titanium dioxide (titania, TiO2) in a setup with a plasmachemical flow reactor were investigated. The synthesis of titania particles from gaseous titanium tetrachloride (TiCl4) in the plasmachemical reactor by the chloride method was experimentally studied. The processes of formation and growth of particles depending on the type of the plasma-forming gas, flow rates of TiCl4; and the quenching gas (air), reactor length, and mean-mass temperature in the reaction zone were considered. When using nitrogen as heat-carrying gas, a new approach of titania powder synthesis based on combining of reaction zone and quenching zone has been applied. Under these non-equilibrium conditions and substantial temperature gradients, this method enabled us to synthesize reproducibly ultrafine titania powders (30–50 nm) with a high content (80–87%) of metastable anatase crystal lattice. The results reveal that the powder properties can be efficiently controlled, i.e., one setup can produce titania with a required particle size and a type of the crystal lattice: anatase (A) or rutile (R). The experimental data are found to agree well with the results of numerical calculations.

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Radtke, Aleksandra. "Photocatalytic Activity of Nanostructured Titania Films Obtained by Electrochemical, Chemical, and Thermal Oxidation of Ti6Al4V Alloy—Comparative Analysis". Catalysts 9, n. 3 (19 marzo 2019): 279. http://dx.doi.org/10.3390/catal9030279.

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Three different Ti6Al4V surface oxidation methods have been applied to obtain three types of titania materials of different nanoarchitecture. Electrochemical oxidation of titanium alloy allowed for obtaining titania nanotubes (TNT), chemical oxidation led to obtain titania nanofibers (TNF), and thermal oxidation gave titania nanowires (TNW). My earlier investigations of these nanomaterials were focused mainly on the estimation of their bioactivity and potential application in modern implantology. In this article, the comparative analysis of the photocatalytic activity of produced systems, as well as the impact of their structure and morphology on this activity, are discussed. The activity of studied nanomaterials was estimated basis of UV-induced degradation of methylene blue and also acetone, and it was determined quantitatively according to the Langmuir–Hinshelwood reaction mechanism. The obtained results were compared to the activity of Pilkington Glass ActivTM (reference sample). Among analyzed systems, titania nanofibers obtained at 140 and 120 °C, possessing anatase and anatase/amorphous structure, as well as titania nanowires obtained at 475 and 500 °C, possessing anatase and anatase/rutile structure, were better photocatalyst than the reference sample. Completely amorphous titania nanotubes, turned out to be an interesting alternative for photocatalytic materials in the form of thin films, however, their photocatalytic activity is lower than for Pilkington Glass ActivTM.

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Shrestha, Sabita, e Chong Yun Park. "Deposition of Titania Nanoparticles on the Surface of Acid Treated Multiwalled Carbon Nanotubes". Advanced Materials Research 117 (giugno 2010): 27–32. http://dx.doi.org/10.4028/www.scientific.net/amr.117.27.

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Titanium dioxide (Titania, TiO2) nanoparticles have been deposited on the surface of acid treated multi-walled carbon nanotubes (MWCNTs) by simple chemical route. The resultant TiO2/MWCNTs composites were characterized by different techniques. The oxidation of MWCNTs and presence of titania nanoparticles on the surface of MWCNTs is confirmed by transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. TEM image shows the size of titania nanoparticles are around 5 nm. Raman spectroscopy showed the oxidation and functionalization of nanotubes. The TGA curve showed decrease in thermal decomposition temperature of MWCNTs after oxidation and attachment with titania nanoparticles.

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Ranney, Elizabeth, John Mansfield, Kai Sun e Johannes Schwank. "Effects of synthesis conditions on dimensions, structure, and oxygen content of photocatalytically active titania nanotubes". Journal of Materials Research 25, n. 1 (gennaio 2010): 89–95. http://dx.doi.org/10.1557/jmr.2010.0011.

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In this study, we report a method for the formation and characterization of aligned arrays of amorphous titania nanotubes by anodic oxidation in thin titanium films on SiO2 substrates using fluoride-containing electrolytes. Trends in titania nanotube geometries as a function of synthesis conditions were established. A titania nanotube array surface area of approximately 178 m2/g is reported. The titania nanotubes transitioned to the rutile crystal structure when heated in air at 530 °C–705 °C. The degradation of methylene blue under UV light showed that lower fluoride concentrations in the synthesis electrolyte result in higher photocatalytic activity of the titania nanotubes. These results indicate that the synthesis conditions affect the oxygen content of amorphous nanotubes, which determines their physical and chemical properties.

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Zhang, Fanli, Zhiqiang Cheng, Lijuan Kang, Liying Cui, Wei Liu, Guohui Hou, Hongjia Yang e Xiaojuan Xu. "3D controllable preparation of composite CuO/TiO2 nanofibers". RSC Adv. 4, n. 108 (2014): 63520–25. http://dx.doi.org/10.1039/c4ra12208a.

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The preparation and research of nanometer metal oxides has drawn considerable attention because of their special structure and excellent chemical properties, particularly titania and titanium dioxide composite nanomaterials.

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KONDAWAR, S. B., S. R. THAKARE, V. KHATI e S. BOMPILWAR. "NANOSTRUCTURE TITANIA REINFORCED CONDUCTING POLYMER COMPOSITES". International Journal of Modern Physics B 23, n. 15 (20 giugno 2009): 3297–304. http://dx.doi.org/10.1142/s0217979209052583.

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Composites of polyaniline with synthesized nanostructured titania ( TiO 2) and polyaniline with commercial TiO 2 have been in situ synthesized by oxidative chemical polymerization method. Sulfuric acid was used as dopant during the polymerization process. Sol-gel precipitates of nanostructured titania were synthesized by hydrolyzing the mixture of titanium chloride ( TiCl 3) and colloidal transparent solution of starch. Composite materials were subjected for comparison to spectroscopic and X-ray diffraction analysis. Strong coupling/interaction of titania with the imine nitrogen in polyaniline confirmed by FTIR spectral analysis. XRD shows the composite of synthesized titania with polyaniline have broaden peak as compared to that of commercial titania with polyaniline indicating particle size in the range of nanometer scale which is supported by 40 nm particle size of the synthesized titania from TEM picture. Increase in conductivity with increasing temperature was observed in both the composite materials.

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Più fonti

Tesi sul tema "Titania (Chemical)"

Sotelo-Vazquez, C. "Modification of titania films by chemical vapour deposition for enhanced photocatalysis". Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1553144/.

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Titanium dioxide (TiO2) is the leading material for self-cleaning applications due to its intrinsic properties, such as chemical inertness, mechanical robustness, high photocatalytic activity and durability to extend photocatalytic cycling. However, its relatively wide bandgap limits its outdoor applications. There has been a strenuous effort to try and improve the photocatalytic efficiency of TiO2, in particular by modifying its electronic structure to enhance its function under solar illumination. The most commonly studied approaches for achieving this have been to incorporate anionic and/or cationic species into the TiO2 structure and the design of TiO2-based heterojunction systems. The addition of nitrogen, phosphorus and sulfur species into the matrix of TiO2 was investigated. Films were grown using atmospheric-pressure chemical vapour deposition (APCVD). The nitrogen-doped system has been investigated most prominently to enhance and extend the photocatalytic response of TiO2 materials into the visible region of the electromagnetic spectrum. Nitrogen can either replace oxygen sites (Ns, substitutional doping) or sit within the TiO2 structure (Ni, interstitial doping) and form N-O groups with lattice oxygen. Interestingly, these NOx groups, as well as NHx surface species present similar binding energies, ca. 400 eV, hindering the identification of the nitrogen species and their role in the photocatalytic response of the material. Various synthesis conditions were experimented using different nitrogen precursors (tert-butylamine, benzylamine and ammonia), which were used to establish a correlation between surface and bulk nitrogen species and the photocatalytic behaviour of the N-TiO2 films. A loss of the Ni environment (as observed by X-ray photoelectron spectroscopy), as well as a decrease in photoactivity over time was observed, suggesting a direct participation of the nitrogen species in photocatalytic iv processes. In addition to traditional CVD methods, a pulse precursor approach was used for the first time, to the best of our knowledge, to synthesise stratified N-doped TiO2 thin films, by adding nitrogen into specific regions of the N-TiO2 film. Physical and functional comparison of stratified and non-stratified N-TiO2 films with similar structural and morphological features allowed us to evaluate the benefits of this synthetic approach, which not only resulted in an increase in the photocatalytic efficiency of the stratified N-TiO2 films but also did not affect the overall crystallinity of the films. The addition of phosphorus and sulfur was investigated as the most promising alternative to the use of nitrogen doping, as both could be added to the lattice of TiO2 either as cations or anions. Through functional testing, it was found that both dopant species were beneficial from a photocatalytic point of view. Interestingly, the use of APCVD techniques to deposit P-TiO2 thin films resulted in the addition for the first time, to the best of our knowledge, of P3- species, as well as P5+, to the TiO2 structure with the relative proportion being determined by the synthesis conditions. Through Hall effect probe, photocatalytic testing and transient absorption spectroscopy (TAS) analyses, it was found that the incorporation of P3- species was detrimental from an electrical conduction and photocatalytic point of view; however, the presence of solely P5+ species resulted in P-TiO2 films with enhanced self-cleaning and TCO properties. These results provide important insights on the influence of dopant nature and its location within a semiconductor’s structure. Heterojunction semiconductor materials are used in a wide range of applications including catalysis, electronic devices, sensors and solar-to-chemical energy conversion. These materials benefit from effective electron transfer processes, electron tunnelling, surface passivation and other synergistic effects to enhance their performance beyond the individual components. By using CVD methods, two different v heterojunction systems, rutile/ anatase TiO2 and WO3/TiO2, were grown. The interposition of an amorphous TiO2-based interlayer allowed direct vapour deposition of anatase on a rutile substrate, which is otherwise hindered by templating. The subsequent crystallisation of the amorphous interlayer after annealing, allowed us to investigate the impact of an efficient interface between the two rutile-anatase phases in the photodegradation of an organic model pollutant, stearic acid. Clear evidence on the synergy between the two polymorphs and more importantly, on the charge flow across the interface, which is against much conventional understanding, was evaluated through the photoreduction of silver particles. This charge flow involves electron transfer from rutile to anatase. Likewise, a conformal coating of WO3 nanorods with TiO2 was performed using APCVD techniques. The resulting WO3/TiO2 heterojunction films showed an electron transfer phenomenon, where electrons moved from WO3 into TiO2, against widely reported observation. State-of-the-art hybrid density functional theory (DFT) and hard X-ray photoelectron spectroscopy (HAXPES) were employed to elucidate the electronic interaction at the heterojunction of the WO3 and TiO2 crystalline phases. This vectorial charge separation reduces electron-hole recombination and most likely extends the lifetime and relative population of photogenerated charges. These results provide important insights on the influence of vectorial charge separation in heterojunctions. These phenomena had a dramatic impact on the photocatalytic efficiency of the heterojunction films, which are among the very highest ever reported by a thin film.

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Liao, Xiaohong. "The synthesis of nano titania particles using a DC transferred arc plasma reactor". Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104690.

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The effect of quench conditions on the properties of titanium dioxide produced using atransferred arc process was studied. Rutile phase TiO2 in the form of micron sized powder wasdecomposed and vaporized in a continuous feed DC transferred arc system. The hot gas streamexiting the reactor contained a mixture of the decomposition products of titania includingtitanium suboxides (TiO, Ti2O3), argon (Ar), and oxygen (O2). Rapid quenching of this gasstream with dry air resulted in the production of a titania aerosol. Collection of the product tookplace in the filtration system. The quench conditions studied included pre-quenchtemperature, T1, quench rate, Rq, residence time, tau , and operating power, Ptorch . Thecharacterization of particles includes phase identification, phase content calculation, sizedistribution analysis, elemental composition analysis, and morphology examination.The range of quench conditions studied were as follows, 1300 < T1 < 1700K, 8000 < Rq < 18000K/s, 50 < tau < 80ms, 7.6 < Ptorch < 12.0kW. In general, high quench rate producedsmall size and high surface area products. Residence time had no obvious effect on product sizeand crystal phase formation. Low operating power produced a high anatase fraction product. Inall cases, spherical particles of a polymorphous mixture of anatase and rutile with no evidence ofsintering were produced. Particle size ranged from less than 10 to 300nm. A representativesample has the mode of 22.3nm, median of 28.1nm and geometric standard deviation of 1.6nm.
L'effet des conditions de trempe sur les propriétés du dioxyde de titane produit par unprocédé à arc transféré a été étudié. Des poudres de TiO2 de la phase rutile et de taillemicrométrique ont été alimentées en continu dans un arc à courant continu (CC), décomposées etvaporisées. Le flux de gaz chauds sortant du réacteur contenait un mélange de produits dedécomposition : notamment de l'oxyde de titane (TiO), du Ti2O3, de l'argon (Ar) et de l'oxygène(O2). Une trempe rapide de cet écoulement de gaz avec de l'air sec a abouti à la production d'unaérosol d'oxyde de titane qui fût ensuite récupéré avec l'aide d'un système de filtration. Lesconditions opératoires étudiées comprenaient la température initiale avant la trempe, T1 , lavitesse de trempe, Rq , le temps de résidence, tau , et la puissance de l'arc, Ptorch . La phase, lateneur de la phase, la distribution de taille, la composition élémentaire ainsi que la morphologiedes poudres produites ont été obtenus.La gamme de conditions de trempe étudiées était la suivante : 1300 < T1 < 1700 K, 8000 < Rq < 18000 K/s, 50 < tau < 80 ms, 7.6 < Ptorch < 12.0 kW. En général, les taux de trempe élevés ontgénéré des poudres de petite taille et surface spécifique élevée. Le temps de résidence n'a euaucun effet évident sur la taille des poucres ainsi que sur la formation de la phase cristalline. Unefaible puissance d'opération de la torche mène à la formation de poudres ayant une forteproportion de la phase anatase. Dans tous les cas, des poudres sphériques constituées d'unmélange polymorphe d'anatase et de rutile, sans apparence de frittage, ont été produites. La taillecharactéristique des poudres varie de 10 à 300 nm. Un échantillon représentatif a montré unmode de 22.3 nm, une médiane de 28.1 nm et une écart type géométrique de 1.6 nm.

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Yoshikawa, Naruo. "The chemical and photochemical reactivity of modified and unmodified high area titania surfaces". Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343010.

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Kang, Chin-Shuo. "CONTROL OF TITANIUM DIOXIDE NANOFIBER CRYSTALLINITY, PARTICLE SIZE AND MORPHOLOGY". University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron161960479044817.

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Stewart, Gregory D. "Numerical simulation of titania deposition in a cold-walled impinging jet type APCVD reactor". Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1178908165.

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PENA, DONOVAN ALEXANDER. "DEVELOPMENT AND CHARACTERIZATION OF MIXED OXIDE CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NITRIC OXIDE FROM STATIONARY SOURCES USING AMMONIA". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054307250.

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Kafizas, A. G. "Combinatorial atmospheric pressure chemical vapour deposition for optimising the functional properties of titania thin-films". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1334459/.

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Titanium dioxide (TiO2) is the leading material for self-cleaning applications due to its chemical inertness, mechanical robustness, durability to extended photocatalytic cycling, low cost and high photocatalytic activity. There has been a concerted effort to try and improve the material’s functional properties through impurity doping; altering the band structure and electronic transport properties. However, any improvements are difficult to optimise using traditional methods. Thin-film combinatorial methods have heralded the discovery of more than 20 new families of materials since their resurgence in the mid-90’s. Such methods enable a high diversity of states to be produced in a single deposition and are now being used more prominently to optimise the functional properties of existing materials. Atmospheric pressure chemical vapour deposition (APCVD) has been applied in a combinatorial fashion to deposit thin-films containing compositional gradients and is also the native method in which thin-films of TiO2 are mass-produced. Utilising combinatorial APCVD, we investigated N, Nb and W doped TiO2 thin-film systems. The Ndoped TiO2 system has been studied most prominently for improved visible light photocatalysis. Nitrogen can either substitute oxygen sites (substitutional doping - Ns) or enter within the TiO2 framework (interstitial doping - Ni), yet there is little consensus on which type of doping or dopant concentration yields the more active photocatalyst. Using the combinatorial APCVD approach, TiCl4 and ethyl acetate precursors were used to form the host TiO2 matrix with either NH3 or t-butylamine used as the N-sources. From three separate investigations we were able to produce combinatorial films with transitional composition/ phase gradients of (i) Ns/ Ni-doped to pure Ni-doped anatase TiO2 (0 ≤ Ns: Ti ≤ 8.4 %, 0.57 ≤ Ni: Ti ≤ 3.3 %), (ii) Ns-doped anatase TiO2 and rutile TiO2 phase mixtures (0 ≤ Ns: Ti ≤ 11 %, 0 ≤ anatase TiO2 ≤ 100 %, 0 ≤ rutile TiO2 ≤ 41 %) and (iii) pure pseudo-brookite Ti3-δO4N to pure Ni-doped anatase TiO2 phase mixtures. In tailoring high-throughput screening methods to these systems we were able to characterise large numbers of unique states across each combinatorial system and inter-relate their physical and functional properties. It was found that (i) pure Ni-doped anatase TiO2 is a more photocatalytically active material than Ns-doped anatase TiO2 under UVA and visible light (> 420 nm), (ii) un-doped anatase TiO2 is more photocatalytically active than Ns-doped anatase TiO2 under UVA light and (iii) pseudo-brookite Ti3-δO4N is a more active photocatalyst than Ni-doped anatase TiO2 under UVA light. The photocatalytic activity of Nb and W doped TiO2 solid solutions had not previously been investigated; however, their film resistivities for potential applications as more durable transparent conducting oxide materials had been. Using combinatorial APCVD we were able to produce NbxTi1-xO2 (0.0004 ≤ x ≤ 0.0194) and WxTi1-xO2 (0.0038 ≤ x ≤ 0.1380) anatase TiO2 thin-film solid solutions with transitional composition gradients. The Nbdoped system was formed from combining TiCl4, ethyl acetate and NbCl5 precursors. By characterising the film with our screening methods were we able to determine the strong functional inter-relationship between the material’s bandgap, photocatalytic activity and film resistivity in three dimensions; where an increased photocatalytic activity was associated with a lower bandgap energy and electrical resistance. The importance of oxygen vacancies on increasing charge carrier mobility presided over the number of charge carriers in the system (Nb-doping level). The W-doped system was formed from combining TiCl4, ethyl acetate and WCl6 precursors. Using high-throughput screening methods once more, the strong physical inter-relationship between the material’s Raman shift, unit cell volume and W-doping level were determined; where increased W-doping increasingly expanded the unit cell in the a/b axis and caused the prominent Raman active Eg vibrational mode of (144 cm-1) to shift to higher energies. Increased W-doping increasingly disrupted crystallisation, yielding less active photocatalysts. More interestingly however, increased preferred orientation in the (211) plane induced a greater degree of photo-induced surface wetting. Given the mechanism for the photo-induced wetting process in anatase TiO2 is, to our knowledge, yet to be studied, the trends highlighted the importance of the (211) plane in this process. Films synthesized by the combinatorial APCVD route, analysed in conjunction with high-throughput characterisation methods, provide a shortcut to understanding and optimising the functional properties of composition/ phase space.

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Marszewski, Michal. "Development of highly porous crystalline titania photocatalysts". Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1476281107453411.

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Hodgkinson, John L. "Atmospheric pressure glow discharge plasma enhanced chemical vapour deposition of titania and aluminium based thin films". Thesis, University of Salford, 2009. http://usir.salford.ac.uk/26717/.

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Atmospheric pressure glow discharge (APGD) plasma CVD was used to deposit thin films of titania at 200 °C using two different precursors. The resulting films were characterised using techniques including XPS, RBS and XRD. It was established that annealing at temperatures as low as 275 °C produced crystalline films that were photocatalytically active. When annealed at 300 °C, the photoactivity was greater than that of a commercially available "self-cleaning" titania film. The effects of the different precursors, annealing times and temperatures on the crystallinity and photoactivity are discussed. This thesis also describes first reported deposition of aluminium oxide thin films by APGD, plasma-enhanced CVD. This approach allows deposition at substantially lower substrate temperatures than normally used in atmospheric pressure based processing. The films are analysed by SEM, XPS, RBS, XRD, and optical properties. It is demonstrated that the APGD approach yields films which are essentially smooth, conformal and free from pinholes or other imperfections. Further novel work was undertaken exploring the deposition of composite metal/ metal oxide thin films using APGD CVD. The described approach employs a parallel- plate dielectric barrier configuration, and the deposition of such materials is discussed with respect to their influence on discharge conditions. Controlled and variable composition films were produced based on aluminium which showed metallic-like reflection (up to 60% visible), and were conductive (~1 O per square). The films were analysed by RBS, SEM, AFM and optical spectroscopy. This new class of APGD-CVD derived thin film material, when combined with the associated low thermal load and attractions for industrial scaling, offers significant potential for new applications. The studies resulted in three full papers, and four posters.

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Pettit, Sandra L. "Investigation of TiO2 and InVO4-TiO2 Semiconductors for the Photocatalytic Degradation of Aqueous Organics". Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5103.

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Water is a vital natural resource. To develop more sustainable water systems, we must focus efforts on the removal of persistent contaminants. Aqueous organic contaminants include azo dyes, halogenated organics (e.g. pesticides), and algal and bacterial metabolites. The latter are common to surface waters and freshwater aquaculture systems and can cause taste and odor problems. Two of the principal organoleptic compounds are geosmin and 2-methylisoborneol (MIB). Traditional oxidation treatment methods, utilizing chlorine, hydrogen peroxide, and potassium permanganate, have been employed with varying levels of efficacy for removal of these and other organic contaminants. Advanced Oxidation Processes (AOPs) have greater potential for the removal of persistent contaminants than traditional methods due to their higher pollutant removal rates, their ability to degrade a variety of organic material, and their ability to completely mineralize compounds [1]. An emerging AOP technology is the use of titania based photocatalysts for water treatment. Titanium dioxide (TiO2) is an effective, inexpensive, and stable photocatalyst used for the decomposition of aqueous organics. Titania is primarily activated by the ultraviolet portion of the spectrum due to its energy band gap of 3.0-3.2 eV (depending upon crystalline structure). Photocatalytic efficiency can be enhanced or tuned through the use of semiconductor dopants and the variance of titania crystal structure (i.e. anatase to rutile ratios). Metal oxides, like indium vanadate (InVO4), may enhance reaction rates through new interfacial reaction sites and electron scavenging, transport, and storage. InVO4 has been shown to have four sub-bandgap transitions, of which three are in the visible range [2]. In this work, the synthesis of InVO4-TiO2 composite semiconductors is examined to shift photo-initiation into the visible portion of the spectrum. Parametric studies of the visible spectrum photodegradation of methyl orange, an azo dye, and 2-chlorophenol provide a basis for analysis. Methyl orange was utilized to ascertain the effect of pure and mixed phase titania in the semiconductor composites. The TiO2 photodegradation of geosmin and MIB has been previously demonstrated in small-scale batch slurry reactions. Slurry systems require the downstream separation of catalyst from the liquid. Laboratory trials use centrifugation or micro-filtration. Alternatively, immobilization of the photocatalyst could allow scale-up of the process. Here, titania was immobilized on glass plate substrates using an ethanol spray technique. Finally, naturally tainted waters may contain a number of constituents in addition to the target compounds. In recirculating aquaculture systems, the water contains natural organic matter (NOM), ammonia, nitrite/ nitrate, and carbonate species. These constituents may block light penetration, block reaction sites, scavenge hydroxyl radicals, or affect the surface chemistry of the catalyst. Further, geosmin and MIB concentrations are extremely low, in the ppt range. Naturally tainted waters from MOTE Marine Laboratory Aquaculture Research Park are treated in the laboratory and in situ to demonstrate TiO2 degradation efficiency for trace concentration geosmin and MIB degradation in a complex water matrix.

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Libri sul tema "Titania (Chemical)"

Kandasamy, Ispran S. Metalorganic chemical vapour deposited titanium dioxide thin films. Uxbridge: Brunel University, 1988.

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Jan Cornelis van der Waal. Synthesis, characterization and catalytic application of zeolite titanium beta. Delft: Delft Univ. Press, 1998.

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McLean, Steven. Chemical vapour deposition of titanium carbide on low alloy high speed steel. Birmingham: University of Birmingham, 1987.

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Piszczek, Piotr. Związki koordynacyjne srbra(I) i tytanu(IV) z ligandami karboksylanowymi jako prekursory chemicznego osadzania metalicznego srebra i ditlenku tyanu z fazy gazowej. Toruń: Wydawn. Nauk. Uniwersytetu Mikołaja Kopernika, 2000.

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Sloof, Willem Gerrit. Internal stresses and microstructure of layer/substrate assemblies: Analysis of TiC and TiN coatings chemically vapour deposited on various substrates. Delft, Netherlands: Delft University Press, 1996.

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Bliznakovska, Blagica. PACVD of TiN. Jülich: Forschungszentrum Jülich, 1995.

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International Agency for Research on Cancer e World Health Organization, a cura di. Carbon black, titanium dioxide, and talc. Lyon, France: International Agency for Research on Cancer, 2010.

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Priestner, Deborah Mary. An investigation of the chemical vapour deposition of titanium carbide onto pre-carburised low carbon, low alloy steel substrates. Birmingham: University of Birmingham, 1989.

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Weikle, Donald H. TiCl₄ as a source of TiO₂ particles for laser anemometry measurements in hot gas]. [Washington, D.C: National Aeronautics and Space Administration, 1990.

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International ASM Conference on High Temperature Aluminides and Intermetallics (2nd 1991 San Diego, Calif.). High temperature aluminides and intermetallics: Proceedings of the Second International ASM Conference on High Temperature Aluminides and Intermetallics, September 16-19, 1991, San Diego, CA, USA. A cura di Whang Sung-Hyun 1936-, Pope D. P, Liu C. T. 1937- e ASM International. London: Elsevier Applied Science, 1992.

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Capitoli di libri sul tema "Titania (Chemical)"

Janczarek, Marcin, e Ewa Kowalska. "Gas-Phase Synthesis of Anatase Titania Nanocrystals with Controlled Structural Properties". In Practical Aspects of Chemical Engineering, 99–109. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39867-5_11.

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Bwana, Nicholas N. "Application of Highly Ordered Arrays of Titania-Coated Titanium Nanorods in Enhanced Photoelectro Chemical Cells". In Proceedings of ISES World Congress 2007 (Vol. I – Vol. V), 1073–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-75997-3_209.

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Smirnova, O., A. Grebenyuk, O. Linnik e V. Lobanov. "Quantum Chemical Study of Water Molecule Adsorption on the Nitrogen-Doped Titania Thin Films". In Springer Proceedings in Physics, 603–9. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56422-7_45.

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Park, Jae Hyeon, Seung Young Lee, Dal Hee Bae, Nam Yun Lim e Jin Wook Ha. "The Effect of Substrates on the Characteristics of Titania Nano-Coated Particles Prepared by Fluidized Bed Chemical Vapor Deposition (FBCVD)". In Materials Science Forum, 126–29. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-995-4.126.

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Habashi, Fathi. "Titanium, Physical and Chemical Properties". In Encyclopedia of Metalloproteins, 2251–52. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-1533-6_374.

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Schmidt, M. "Chemical Reactions at Titanium Surfaces". In The Thrust Plate Hip Prosthesis, 133–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60502-4_12.

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Bastasz, R. "Hydrogen Profiling in Titanium". In Springer Series in Chemical Physics, 397–99. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82724-2_106.

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Stewart, Kerrilee A., e Harinder Pal Singh Missan. "Wet Chemical Approaches for Chemical Functionalization of Silicon and Titanium Nanomaterials". In Handbook of Nanoelectrochemistry, 1–14. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15207-3_45-1.

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Stewart, Kerrilee A., e Harinder Pal Singh Missan. "Wet Chemical Approaches for Chemical Functionalization of Silicon and Titanium Nanomaterials". In Handbook of Nanoelectrochemistry, 849–65. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15266-0_45.

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Li, Guangqiang. "Principles of Chemical Metallurgy of Titanium Microalloyed Steel". In Titanium Microalloyed Steel: Fundamentals, Technology, and Products, 35–69. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3332-3_2.

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Atti di convegni sul tema "Titania (Chemical)"

Luo, Fei, Guojie Xu, Yan Liu, Chunling Xie e Xiufeng Xiao. "PEG-Coated Titania Nanatubes for Controlled Drug Release". In International Conference on Chemical,Material and Food Engineering. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/cmfe-15.2015.27.

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Jindarat, Tossaporn, Somchai Osuwan, Suchada Butnark e Siriporn Jongpatiwut. "Deoxygenation of Beef Fat over Pd Supported Mesoporous Titania Catalysts". In 14th Asia Pacific Confederation of Chemical Engineering Congress. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-1445-1_447.

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Nguyen, Son Truong, e Xin Wang. "Exploration of Nb-doped Titania as Catalyst Support for Alkaline Direct Ethanol Fuel Cell". In 14th Asia Pacific Confederation of Chemical Engineering Congress. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-1445-1_291.

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Nikhil, S. K., e G. Nair Ranjith. "Role of alcohol solvents on physico-chemical characteristics and photocatalytic performance of titania". In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5130302.

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Liou, Tzong-Horng, Bo-Chen Lai e Bin-Joen Tsay. "The Synthesis of the Mesoprous Silica Catalyst Support and Highly Enhanced Photocatalytic Activity of Supported Titania Nanoparticles". In 14th Asia Pacific Confederation of Chemical Engineering Congress. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-1445-1_723.

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Heltina, Desi, Praswasti P. D. K. Wulan e Slamet. "Photocatalytic activity of titania nanotube (tint)-carbon nanotube (CNT) composite for degradation of phenol". In INTERNATIONAL SEMINAR ON FUNDAMENTAL AND APPLICATION OF CHEMICAL ENGINEERING 2016 (ISFAChE 2016): Proceedings of the 3rd International Seminar on Fundamental and Application of Chemical Engineering 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4982305.

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Flak, Dorota, Mieczyslaw Rekas, Artur Braun e Antje Vollmer. "P2.4.8 Effect of the Titania Substitution on the Electronic Structure and Transport Properties of FSS-made Fe2O3 Nanoparticles for Hydrogen Sensing". In 14th International Meeting on Chemical Sensors - IMCS 2012. AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany, 2012. http://dx.doi.org/10.5162/imcs2012/p2.4.8.

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Tiwari, D., S. W. James, R. P. Tatam, S. Korposh e S. W. Lee. "A high-sensitivity chemical sensor based on titania coated optical-fiber long period grating for ammonia sensing in water". In Fifth Asia Pacific Optical Sensors Conference, a cura di Byoungho Lee, Sang-Bae Lee e Yunjiang Rao. SPIE, 2015. http://dx.doi.org/10.1117/12.2184260.

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Tao Sun e Min Wang. "Chemical stability of the titania layer formed synthetically on NiTi shape memory alloy as a barrier to prevent nickel ion release". In 2008 International Conference on Technology and Applications in Biomedicine (ITAB). IEEE, 2008. http://dx.doi.org/10.1109/itab.2008.4570641.

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Omegna, Federica, Gianfranco Genta, Emanuele M. Barini, Daniele L. Marchisio e Raffaello Levi. "Sensitivity Testing Revisited: The Case of Sol-Gel Transition". In ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2008. http://dx.doi.org/10.1115/esda2008-59091.

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Classical sensitivity testing addresses mainly problems where the level of one stimulus only governs an abrupt transition in output, or response. Both parametric and nonparametric methods developed, and successfully applied over last century to tackle such problems, provide estimates of critical levels beyond which an item will either respond, or not, to a single stimulus, and of related statistics. However classical methods sometimes may not readily provide an answer, namely when more than one stimulus may reach critical level, and either singularly or jointly trigger transition. Factorial and response surface designs, adequate when dealing with continuous responses, may not perform as well for transition threshold estimation. A practical case at hand in chemical engineering concerns the production, through hydrolysis of a specific precursor, of titania sols and gels that find industrial use as additive for paints, concrete and other building materials due to its optical, photo-catalytic and super-hydrophilic properties. Particles formation and aggregation — controlled by varying the primary process parameters, namely initial alkoxide concentration, water to alkoxide and acid to alkoxide ratios, mixing conditions — may yield either stable, transparent nanometric sols, or monolithic gels, where aggregation of nanometric particles produces a final ceramic object. Depending on the application, one of the two products may be desirable, and therefore it is crucial to control the final product properties. Aggregation kinetics and physical properties of sols, and sol to gel transition, were found to depend strongly upon several factors, that is water to alkoxide initial concentration ratio, acid to alkoxide initial concentration ratio, and their interaction. The approach developed in order to estimate parameters pertaining to transition, and related uncertainty, is presented in the paper, and discussed in the light of experimental results.

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Rapporti di organizzazioni sul tema "Titania (Chemical)"

Parrish, R. R., D. Bellerive e R. W. Sullivan. U - Pb Chemical Procedures For Titanite and Allanite in the Geochronology Laboratory, Geological Survey of Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1992. http://dx.doi.org/10.4095/132925.

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David, W. J., V. J. McNicoll, D. R. Bellerive, K. Santowski e D. J. Scott. Modified chemical procedures for the extraction and purification of uranium from titanite, allanite, and rutile in the Geochronology Laboratory, Geological Survey of Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1997. http://dx.doi.org/10.4095/209090.

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